Electronic messaging, particularly email, has become a preferred way of communication for many individuals and organizations. Unfortunately, email recipients are increasingly becoming subject to unsolicited or otherwise unwanted email messages, such as “spam”; such messages are referred to herein as “abusive”. There are many anti-spam products on the market today that can help identify abusive email messages. These anti-spam tools work either at the gateway (the corporate mail server and/or ISP) or on the end-user's machine (e.g., a laptop computer, desktop computer, etc.). An increasing number of corporations use both.
Current anti-spam tools usually inspect the whole message—the headers and the body—to come to a determination about the email message. They might be effective in detecting certain specific types of abusive email messages based on their content, such as unsolicited advertisement, virus, etc., but they are not designed to detect general abusive email messages and email messages intended for network resource abuses. Furthermore, inspecting the message body using so-called content filtering demands time and resources and can be easily overcome by spammers by changing the content style. Spammers can also slow down the anti-spam tools by increasing the content volume of the abusive email message.